package docker
import (
"encoding/json"
"fmt"
"github.com/dotcloud/docker/rcli"
"github.com/kr/pty"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path"
"strconv"
"syscall"
"time"
)
type Container struct {
root string
Id string
Created time.Time
Path string
Args []string
Config *Config
State State
Image string
network *NetworkInterface
NetworkSettings *NetworkSettings
SysInitPath string
cmd *exec.Cmd
stdout *writeBroadcaster
stderr *writeBroadcaster
stdin io.ReadCloser
stdinPipe io.WriteCloser
ptyStdinMaster io.Closer
ptyStdoutMaster io.Closer
ptyStderrMaster io.Closer
runtime *Runtime
}
type Config struct {
Hostname string
User string
Memory int64 // Memory limit (in bytes)
MemorySwap int64 // Total memory usage (memory + swap); set `-1' to disable swap
AttachStdin bool
AttachStdout bool
AttachStderr bool
PortSpecs []string
Tty bool // Attach standard streams to a tty, including stdin if it is not closed.
OpenStdin bool // Open stdin
StdinOnce bool // If true, close stdin after the 1 attached client disconnects.
Env []string
Cmd []string
Image string // Name of the image as it was passed by the operator (eg. could be symbolic)
}
func ParseRun(args []string, stdout io.Writer) (*Config, error) {
cmd := rcli.Subcmd(stdout, "run", "[OPTIONS] IMAGE COMMAND [ARG...]", "Run a command in a new container")
if len(args) > 0 && args[0] != "--help" {
cmd.SetOutput(ioutil.Discard)
}
flHostname := cmd.String("h", "", "Container host name")
flUser := cmd.String("u", "", "Username or UID")
flDetach := cmd.Bool("d", false, "Detached mode: leave the container running in the background")
flAttach := NewAttachOpts()
cmd.Var(flAttach, "a", "Attach to stdin, stdout or stderr.")
flStdin := cmd.Bool("i", false, "Keep stdin open even if not attached")
flTty := cmd.Bool("t", false, "Allocate a pseudo-tty")
flMemory := cmd.Int64("m", 0, "Memory limit (in bytes)")
var flPorts ListOpts
cmd.Var(&flPorts, "p", "Expose a container's port to the host (use 'docker port' to see the actual mapping)")
var flEnv ListOpts
cmd.Var(&flEnv, "e", "Set environment variables")
if err := cmd.Parse(args); err != nil {
return nil, err
}
if *flDetach && len(flAttach) > 0 {
return nil, fmt.Errorf("Conflicting options: -a and -d")
}
// If neither -d or -a are set, attach to everything by default
if len(flAttach) == 0 && !*flDetach {
if !*flDetach {
flAttach.Set("stdout")
flAttach.Set("stderr")
if *flStdin {
flAttach.Set("stdin")
}
}
}
parsedArgs := cmd.Args()
runCmd := []string{}
image := ""
if len(parsedArgs) >= 1 {
image = cmd.Arg(0)
}
if len(parsedArgs) > 1 {
runCmd = parsedArgs[1:]
}
config := &Config{
Hostname: *flHostname,
PortSpecs: flPorts,
User: *flUser,
Tty: *flTty,
OpenStdin: *flStdin,
Memory: *flMemory,
AttachStdin: flAttach.Get("stdin"),
AttachStdout: flAttach.Get("stdout"),
AttachStderr: flAttach.Get("stderr"),
Env: flEnv,
Cmd: runCmd,
Image: image,
}
// When allocating stdin in attached mode, close stdin at client disconnect
if config.OpenStdin && config.AttachStdin {
config.StdinOnce = true
}
return config, nil
}
type NetworkSettings struct {
IpAddress string
IpPrefixLen int
Gateway string
PortMapping map[string]string
}
func (container *Container) Cmd() *exec.Cmd {
return container.cmd
}
func (container *Container) When() time.Time {
return container.Created
}
func (container *Container) FromDisk() error {
data, err := ioutil.ReadFile(container.jsonPath())
if err != nil {
return err
}
// Load container settings
if err := json.Unmarshal(data, container); err != nil {
return err
}
return nil
}
func (container *Container) ToDisk() (err error) {
data, err := json.Marshal(container)
if err != nil {
return
}
return ioutil.WriteFile(container.jsonPath(), data, 0666)
}
func (container *Container) generateLXCConfig() error {
fo, err := os.Create(container.lxcConfigPath())
if err != nil {
return err
}
defer fo.Close()
if err := LxcTemplateCompiled.Execute(fo, container); err != nil {
return err
}
return nil
}
func (container *Container) startPty() error {
stdoutMaster, stdoutSlave, err := pty.Open()
if err != nil {
return err
}
container.ptyStdoutMaster = stdoutMaster
container.cmd.Stdout = stdoutSlave
stderrMaster, stderrSlave, err := pty.Open()
if err != nil {
return err
}
container.ptyStderrMaster = stderrMaster
container.cmd.Stderr = stderrSlave
// Copy the PTYs to our broadcasters
go func() {
defer container.stdout.CloseWriters()
Debugf("[startPty] Begin of stdout pipe")
io.Copy(container.stdout, stdoutMaster)
Debugf("[startPty] End of stdout pipe")
}()
go func() {
defer container.stderr.CloseWriters()
Debugf("[startPty] Begin of stderr pipe")
io.Copy(container.stderr, stderrMaster)
Debugf("[startPty] End of stderr pipe")
}()
// stdin
var stdinSlave io.ReadCloser
if container.Config.OpenStdin {
var stdinMaster io.WriteCloser
stdinMaster, stdinSlave, err = pty.Open()
if err != nil {
return err
}
container.ptyStdinMaster = stdinMaster
container.cmd.Stdin = stdinSlave
// FIXME: The following appears to be broken.
// "cannot set terminal process group (-1): Inappropriate ioctl for device"
// container.cmd.SysProcAttr = &syscall.SysProcAttr{Setctty: true, Setsid: true}
go func() {
defer container.stdin.Close()
Debugf("[startPty] Begin of stdin pipe")
io.Copy(stdinMaster, container.stdin)
Debugf("[startPty] End of stdin pipe")
}()
}
if err := container.cmd.Start(); err != nil {
return err
}
stdoutSlave.Close()
stderrSlave.Close()
if stdinSlave != nil {
stdinSlave.Close()
}
return nil
}
func (container *Container) start() error {
container.cmd.Stdout = container.stdout
container.cmd.Stderr = container.stderr
if container.Config.OpenStdin {
stdin, err := container.cmd.StdinPipe()
if err != nil {
return err
}
go func() {
defer stdin.Close()
Debugf("Begin of stdin pipe [start]")
io.Copy(stdin, container.stdin)
Debugf("End of stdin pipe [start]")
}()
}
return container.cmd.Start()
}
func (container *Container) Attach(stdin io.ReadCloser, stdinCloser io.Closer, stdout io.Writer, stderr io.Writer) chan error {
var cStdout, cStderr io.ReadCloser
var nJobs int
errors := make(chan error, 3)
if stdin != nil && container.Config.OpenStdin {
nJobs += 1
if cStdin, err := container.StdinPipe(); err != nil {
errors <- err
} else {
go func() {
Debugf("[start] attach stdin\n")
defer Debugf("[end] attach stdin\n")
// No matter what, when stdin is closed (io.Copy unblock), close stdout and stderr
if cStdout != nil {
defer cStdout.Close()
}
if cStderr != nil {
defer cStderr.Close()
}
if container.Config.StdinOnce {
defer cStdin.Close()
}
_, err := io.Copy(cStdin, stdin)
if err != nil {
Debugf("[error] attach stdin: %s\n", err)
}
// Discard error, expecting pipe error
errors <- nil
}()
}
}
if stdout != nil {
nJobs += 1
if p, err := container.StdoutPipe(); err != nil {
errors <- err
} else {
cStdout = p
go func() {
Debugf("[start] attach stdout\n")
defer Debugf("[end] attach stdout\n")
// If we are in StdinOnce mode, then close stdin
if container.Config.StdinOnce {
if stdin != nil {
defer stdin.Close()
}
if stdinCloser != nil {
defer stdinCloser.Close()
}
}
_, err := io.Copy(stdout, cStdout)
if err != nil {
Debugf("[error] attach stdout: %s\n", err)
}
errors <- err
}()
}
}
if stderr != nil {
nJobs += 1
if p, err := container.StderrPipe(); err != nil {
errors <- err
} else {
cStderr = p
go func() {
Debugf("[start] attach stderr\n")
defer Debugf("[end] attach stderr\n")
// If we are in StdinOnce mode, then close stdin
if container.Config.StdinOnce {
if stdin != nil {
defer stdin.Close()
}
if stdinCloser != nil {
defer stdinCloser.Close()
}
}
_, err := io.Copy(stderr, cStderr)
if err != nil {
Debugf("[error] attach stderr: %s\n", err)
}
errors <- err
}()
}
}
return Go(func() error {
if cStdout != nil {
defer cStdout.Close()
}
if cStderr != nil {
defer cStderr.Close()
}
// FIXME: how do clean up the stdin goroutine without the unwanted side effect
// of closing the passed stdin? Add an intermediary io.Pipe?
for i := 0; i < nJobs; i += 1 {
Debugf("Waiting for job %d/%d\n", i+1, nJobs)
if err := <-errors; err != nil {
Debugf("Job %d returned error %s. Aborting all jobs\n", i+1, err)
return err
}
Debugf("Job %d completed successfully\n", i+1)
}
Debugf("All jobs completed successfully\n")
return nil
})
}
func (container *Container) Start() error {
if container.State.Running {
return fmt.Errorf("The container %s is already running.", container.Id)
}
if err := container.EnsureMounted(); err != nil {
return err
}
if err := container.allocateNetwork(); err != nil {
return err
}
if err := container.generateLXCConfig(); err != nil {
return err
}
params := []string{
"-n", container.Id,
"-f", container.lxcConfigPath(),
"--",
"/sbin/init",
}
// Networking
params = append(params, "-g", container.network.Gateway.String())
// User
if container.Config.User != "" {
params = append(params, "-u", container.Config.User)
}
// Program
params = append(params, "--", container.Path)
params = append(params, container.Args...)
container.cmd = exec.Command("lxc-start", params...)
// Setup environment
container.cmd.Env = append(
[]string{
"HOME=/",
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
},
container.Config.Env...,
)
// Setup logging of stdout and stderr to disk
if err := container.runtime.LogToDisk(container.stdout, container.logPath("stdout")); err != nil {
return err
}
if err := container.runtime.LogToDisk(container.stderr, container.logPath("stderr")); err != nil {
return err
}
var err error
if container.Config.Tty {
container.cmd.Env = append(
[]string{"TERM=xterm"},
container.cmd.Env...,
)
err = container.startPty()
} else {
err = container.start()
}
if err != nil {
return err
}
// FIXME: save state on disk *first*, then converge
// this way disk state is used as a journal, eg. we can restore after crash etc.
container.State.setRunning(container.cmd.Process.Pid)
container.ToDisk()
go container.monitor()
return nil
}
func (container *Container) Run() error {
if err := container.Start(); err != nil {
return err
}
container.Wait()
return nil
}
func (container *Container) Output() (output []byte, err error) {
pipe, err := container.StdoutPipe()
if err != nil {
return nil, err
}
defer pipe.Close()
if err := container.Start(); err != nil {
return nil, err
}
output, err = ioutil.ReadAll(pipe)
container.Wait()
return output, err
}
// StdinPipe() returns a pipe connected to the standard input of the container's
// active process.
//
func (container *Container) StdinPipe() (io.WriteCloser, error) {
return container.stdinPipe, nil
}
func (container *Container) StdoutPipe() (io.ReadCloser, error) {
reader, writer := io.Pipe()
container.stdout.AddWriter(writer)
return newBufReader(reader), nil
}
func (container *Container) StderrPipe() (io.ReadCloser, error) {
reader, writer := io.Pipe()
container.stderr.AddWriter(writer)
return newBufReader(reader), nil
}
func (container *Container) allocateNetwork() error {
iface, err := container.runtime.networkManager.Allocate()
if err != nil {
return err
}
container.NetworkSettings.PortMapping = make(map[string]string)
for _, spec := range container.Config.PortSpecs {
if nat, err := iface.AllocatePort(spec); err != nil {
iface.Release()
return err
} else {
container.NetworkSettings.PortMapping[strconv.Itoa(nat.Backend)] = strconv.Itoa(nat.Frontend)
}
}
container.network = iface
container.NetworkSettings.IpAddress = iface.IPNet.IP.String()
container.NetworkSettings.IpPrefixLen, _ = iface.IPNet.Mask.Size()
container.NetworkSettings.Gateway = iface.Gateway.String()
return nil
}
func (container *Container) releaseNetwork() {
container.network.Release()
container.network = nil
container.NetworkSettings = &NetworkSettings{}
}
func (container *Container) monitor() {
// Wait for the program to exit
Debugf("Waiting for process")
if err := container.cmd.Wait(); err != nil {
// Discard the error as any signals or non 0 returns will generate an error
Debugf("%s: Process: %s", container.Id, err)
}
Debugf("Process finished")
exitCode := container.cmd.ProcessState.Sys().(syscall.WaitStatus).ExitStatus()
// Cleanup
container.releaseNetwork()
if container.Config.OpenStdin {
if err := container.stdin.Close(); err != nil {
Debugf("%s: Error close stdin: %s", container.Id, err)
}
}
if err := container.stdout.CloseWriters(); err != nil {
Debugf("%s: Error close stdout: %s", container.Id, err)
}
if err := container.stderr.CloseWriters(); err != nil {
Debugf("%s: Error close stderr: %s", container.Id, err)
}
if container.ptyStdinMaster != nil {
if err := container.ptyStdinMaster.Close(); err != nil {
Debugf("%s: Error close pty stdin master: %s", container.Id, err)
}
}
if container.ptyStdoutMaster != nil {
if err := container.ptyStdoutMaster.Close(); err != nil {
Debugf("%s: Error close pty stdout master: %s", container.Id, err)
}
}
if container.ptyStderrMaster != nil {
if err := container.ptyStderrMaster.Close(); err != nil {
Debugf("%s: Error close pty stderr master: %s", container.Id, err)
}
}
if err := container.Unmount(); err != nil {
log.Printf("%v: Failed to umount filesystem: %v", container.Id, err)
}
// Re-create a brand new stdin pipe once the container exited
if container.Config.OpenStdin {
container.stdin, container.stdinPipe = io.Pipe()
}
// Report status back
container.State.setStopped(exitCode)
if err := container.ToDisk(); err != nil {
// FIXME: there is a race condition here which causes this to fail during the unit tests.
// If another goroutine was waiting for Wait() to return before removing the container's root
// from the filesystem... At this point it may already have done so.
// This is because State.setStopped() has already been called, and has caused Wait()
// to return.
// FIXME: why are we serializing running state to disk in the first place?
//log.Printf("%s: Failed to dump configuration to the disk: %s", container.Id, err)
}
}
func (container *Container) kill() error {
if container.cmd == nil {
return nil
}
if err := container.cmd.Process.Kill(); err != nil {
return err
}
// Wait for the container to be actually stopped
container.Wait()
return nil
}
func (container *Container) Kill() error {
if !container.State.Running {
return nil
}
return container.kill()
}
func (container *Container) Stop() error {
if !container.State.Running {
return nil
}
// 1. Send a SIGTERM
if output, err := exec.Command("lxc-kill", "-n", container.Id, "15").CombinedOutput(); err != nil {
log.Print(string(output))
log.Print("Failed to send SIGTERM to the process, force killing")
if err := container.Kill(); err != nil {
return err
}
}
// 2. Wait for the process to exit on its own
if err := container.WaitTimeout(10 * time.Second); err != nil {
log.Printf("Container %v failed to exit within 10 seconds of SIGTERM - using the force", container.Id)
if err := container.Kill(); err != nil {
return err
}
}
return nil
}
func (container *Container) Restart() error {
if err := container.Stop(); err != nil {
return err
}
if err := container.Start(); err != nil {
return err
}
return nil
}
// Wait blocks until the container stops running, then returns its exit code.
func (container *Container) Wait() int {
for container.State.Running {
container.State.wait()
}
return container.State.ExitCode
}
func (container *Container) ExportRw() (Archive, error) {
return Tar(container.rwPath(), Uncompressed)
}
func (container *Container) Export() (Archive, error) {
if err := container.EnsureMounted(); err != nil {
return nil, err
}
return Tar(container.RootfsPath(), Uncompressed)
}
func (container *Container) WaitTimeout(timeout time.Duration) error {
done := make(chan bool)
go func() {
container.Wait()
done <- true
}()
select {
case <-time.After(timeout):
return fmt.Errorf("Timed Out")
case <-done:
return nil
}
panic("unreachable")
}
func (container *Container) EnsureMounted() error {
if mounted, err := container.Mounted(); err != nil {
return err
} else if mounted {
return nil
}
return container.Mount()
}
func (container *Container) Mount() error {
image, err := container.GetImage()
if err != nil {
return err
}
return image.Mount(container.RootfsPath(), container.rwPath())
}
func (container *Container) Changes() ([]Change, error) {
image, err := container.GetImage()
if err != nil {
return nil, err
}
return image.Changes(container.rwPath())
}
func (container *Container) GetImage() (*Image, error) {
if container.runtime == nil {
return nil, fmt.Errorf("Can't get image of unregistered container")
}
return container.runtime.graph.Get(container.Image)
}
func (container *Container) Mounted() (bool, error) {
return Mounted(container.RootfsPath())
}
func (container *Container) Unmount() error {
return Unmount(container.RootfsPath())
}
// ShortId returns a shorthand version of the container's id for convenience.
// A collision with other container shorthands is very unlikely, but possible.
// In case of a collision a lookup with Runtime.Get() will fail, and the caller
// will need to use a langer prefix, or the full-length container Id.
func (container *Container) ShortId() string {
return TruncateId(container.Id)
}
func (container *Container) logPath(name string) string {
return path.Join(container.root, fmt.Sprintf("%s-%s.log", container.Id, name))
}
func (container *Container) ReadLog(name string) (io.Reader, error) {
return os.Open(container.logPath(name))
}
func (container *Container) jsonPath() string {
return path.Join(container.root, "config.json")
}
func (container *Container) lxcConfigPath() string {
return path.Join(container.root, "config.lxc")
}
// This method must be exported to be used from the lxc template
func (container *Container) RootfsPath() string {
return path.Join(container.root, "rootfs")
}
func (container *Container) rwPath() string {
return path.Join(container.root, "rw")
}
func validateId(id string) error {
if id == "" {
return fmt.Errorf("Invalid empty id")
}
return nil
}